Can't bind Value in MicroQualitativeRange

<microcharts:MicroBulletGraph Width="100" Height="15" Grid.Column="2" Padding="2"
                              FeaturedMeasureValue="{Binding Quantity, Converter={StaticResource QuantityConverter}}">
   <microcharts:MicroBulletGraph.QualitativeRanges>
       <microcharts:MicroQualitativeRange Value="{Binding LowRange}"/>
       <microcharts:MicroQualitativeRange Value="{Binding HighRange}"/>
       <microcharts:MicroQualitativeRange />
   </microcharts:MicroBulletGraph.QualitativeRanges>
</microcharts:MicroBulletGraph>

This seems like it should be a "basic" function of these charts and yet it's not possible. Who want's to hard code these ranges in?

Cannot find governing FrameworkElement or FrameworkContentElement for target element. BindingExpression:Path=HighRange; DataItem=null; target element is 'MicroQualitativeRange' (HashCode=21346264); target property is 'Value' (type 'Double')